192 PROCEEDINGS OP THE AMERICAN ACADEMY 



obtained a definite product. From 5 grams of our oil we obtained 

 8.3 grams of a highly crystalline, nearly colorless bromine derivative, 

 which melted at 111-112°, and a single recrystallization sufficed 

 to raise the melting-point to 115-116°. Further recrystallization 

 from alcohol or benzol failed to raise this melting-point. While 

 our product thus melted 14° higher than the tribromguaiacol of 

 Tiemann and Koppe, it agreed in other respects with their de- 

 scription, and the following analyses show that it had the same 

 composition : — 



I. 0.2316 grm. substance gave 0.1974 grm. C0 2 and 0.0345 

 grm. H 2 0. 

 II. 0.1603 grm. substance gave 0.2497 grm. AgBr. 

 III. 0.1705 grm. substance gave 0.2653 grm. AgBr. 



in. 



66.24 



Since we had failed to identify our substance as guaiacol through 

 the melting point of this bromine derivative, we proceeded to pre- 

 pare from it pyrocatechin. For this purpose we used, instead of the 

 more usual hydriodic acid, hydrochloric acid, as W. H. Perkin, Jr.* 

 had recently shown the decomposition was in this case nearly per- 

 fect if the reaction took place in sealed tube at 170-180°. On 

 opening the tube, a gas escaped which burned with a green-bordered 

 flame. The aqueous solution was extracted with ether, and the 

 crystalline residue which was left upon evaporating the ether was 

 distilled. The substance boiled at 240-242°, and the solidified 

 distillate melted at 103-104°. When recrystallized from benzol it 

 formed colorless lustrous scales, which appeared under the micro- 

 scope to be rectangular plates, and melted sharply at 104°. The 

 boiling point of pyrocatechin is usually given at 240-245°, and the 

 melting point was found by Fittig and Mager f to be 104°. In 

 aqueous solution our product also gave with ferric chloride an em- 

 erald-green coloration which turned to a violet-red on the addition 

 of sodic, carbonate. It was thus established with precision that 

 pyrocatechin had been formed by heating with hydrochloric acid 



* Journ. Chem. Soc, LVII. 589. 



t Berichte der deutsch. chem. Gesellsch., VIII. 365. 



